Add Cube controller events

Refactor code:

* Add Cube Registry to keep track of configured cubes
* Add Cube object for interactions with a single Docker Container
* Split between Observing Container lifecycles, executing Controller
events and Object creation

fixes #19
Yea, was wondering the same. PollingAwaiStrategy require more then just the Id tho, as the Inspect request is hidden behind Cube.bindings as it is now. I can update the others to use Cube as well.